/*
 * Copyright (c) 2005, 2006, 2007 Lev Walkin <vlm@lionet.info>.
 * All rights reserved.
 * Redistribution and modifications are permitted subject to BSD license.
 */
#ifndef _PER_SUPPORT_H_
#define _PER_SUPPORT_H_

#include <asn_system.h> /* Platform-specific types */

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Pre-computed PER constraints.
 */
typedef struct asn_per_constraint_s {
  enum asn_per_constraint_flags {
    APC_UNCONSTRAINED = 0x0,    /* No PER visible constraints */
    APC_SEMI_CONSTRAINED = 0x1, /* Constrained at "lb" */
    APC_CONSTRAINED = 0x2,      /* Fully constrained */
    APC_EXTENSIBLE = 0x4        /* May have extension */
  } flags;
  int range_bits;      /* Full number of bits in the range */
  int effective_bits;  /* Effective bits */
  int64_t lower_bound; /* "lb" value */
  int64_t upper_bound; /* "ub" value */
} asn_per_constraint_t;
typedef struct asn_per_constraints_s {
  asn_per_constraint_t value;
  asn_per_constraint_t size;
  int (*value2code)(unsigned int value);
  int (*code2value)(unsigned int code);
} asn_per_constraints_t;

/*
 * This structure describes a position inside an incoming PER bit stream.
 */
typedef struct asn_per_data_s {
  const uint8_t* buffer; /* Pointer to the octet stream */
  size_t nboff;          /* Bit offset to the meaningful bit */
  size_t nbits;          /* Number of bits in the stream */
  size_t moved;          /* Number of bits moved through this bit stream */
  int (*refill)(struct asn_per_data_s*);
  void* refill_key;
} asn_per_data_t;

/*
 * Extract a small number of bits (<= 31) from the specified PER data pointer.
 * This function returns -1 if the specified number of bits could not be
 * extracted due to EOD or other conditions.
 */
int32_t per_get_few_bits(asn_per_data_t* per_data, int get_nbits);

/* Undo the immediately preceeding "get_few_bits" operation */
void per_get_undo(asn_per_data_t* per_data, int get_nbits);

/*
 * Extract a large number of bits from the specified PER data pointer.
 * This function returns -1 if the specified number of bits could not be
 * extracted due to EOD or other conditions.
 */
int per_get_many_bits(asn_per_data_t* pd, uint8_t* dst, int right_align,
                      int get_nbits);

/*
 * Get the length "n" from the Unaligned PER stream.
 */
ssize_t uper_get_length(asn_per_data_t* pd, int effective_bound_bits,
                        int* repeat);

ssize_t aper_get_length(asn_per_data_t* pd, int range, int effective_bound_bits,
                        int* repeat);

/*
 * Get the normally small length "n".
 */
ssize_t uper_get_nslength(asn_per_data_t* pd);
ssize_t aper_get_nslength(asn_per_data_t* pd);

/*
 * Get the normally small non-negative whole number.
 */
ssize_t uper_get_nsnnwn(asn_per_data_t* pd);
ssize_t aper_get_nsnnwn(asn_per_data_t* pd, int range);

/* Non-thread-safe debugging function, don't use it */
char* per_data_string(asn_per_data_t* pd);

/*
 * This structure supports forming PER output.
 */
typedef struct asn_per_outp_s {
  uint8_t* buffer;      /* Pointer into the (tmpspace) */
  size_t nboff;         /* Bit offset to the meaningful bit */
  size_t nbits;         /* Number of bits left in (tmpspace) */
  uint8_t tmpspace[32]; /* Preliminary storage to hold data */
  int (*outper)(const void* data, size_t size, void* op_key);
  void* op_key;         /* Key for (outper) data callback */
  size_t flushed_bytes; /* Bytes already flushed through (outper) */
} asn_per_outp_t;

/* Output a small number of bits (<= 31) */
int per_put_few_bits(asn_per_outp_t* per_data, uint32_t bits, int obits);

/* Output a large number of bits */
int per_put_many_bits(asn_per_outp_t* po, const uint8_t* src, int put_nbits);

/* Align the current bit position to octet bundary */
int aper_put_align(asn_per_outp_t* po);
int32_t aper_get_align(asn_per_data_t* pd);

/*
 * Put the length "n" to the Unaligned PER stream.
 * This function returns the number of units which may be flushed
 * in the next units saving iteration.
 */
ssize_t uper_put_length(asn_per_outp_t* po, size_t whole_length);

ssize_t aper_put_length(asn_per_outp_t* po, int range, size_t length);

/*
 * Put the normally small length "n" to the Unaligned PER stream.
 * Returns 0 or -1.
 */
int uper_put_nslength(asn_per_outp_t* po, size_t length);

int aper_put_nslength(asn_per_outp_t* po, size_t length);

/*
 * Put the normally small non-negative whole number.
 */
int uper_put_nsnnwn(asn_per_outp_t* po, int n);

int aper_put_nsnnwn(asn_per_outp_t* po, int range, int number);

#ifdef __cplusplus
}
#endif

#endif /* _PER_SUPPORT_H_ */
